Oil well pumping apparatus



; June 25, 1946- H. F. VICKERS ETAL 2,402,712

OIL WELL PUMPING APPARATUS Original Filed Jan. 15, 1940 191 F119. 2 fix w .199 jsa INV CR5 2 196 .197 183 200 i/ar I ickers' 18 J96 .Kennet E f/erman M Ms "0.56 gab ATTORNEYS Patented June 25, 1946 OIL WELL PUMPING APPARATUS Harry F. Vickers, Kenneth R. Herman and Jesse Moser, Detroit, Mich., assignors to Vickers Incorporated, Detroit, Mich, a corporation of Michigan Original application January 15, 1940, Serial No.

Divided and this application October 25, 1940, Serial No. 362,818

8 Claims.

This invention relates to a stroke control for variable displacement pumps.

It is an object of the present invention to pro vide a stroke control which 'will greatlyreduce the shock due to change of direction of how through the pump as well as to control the acceleration and deceleration movements where the pump is used in a system in which the speed of an operating member is directly controlled by the pump displacement.

A further object of the invention is to provide a stroke control piston which permits extremely rapid operation, that is, extremely rapid reversals of flow through a variable volume pump.

This is a divisional application of a co-pending application, Serial No. 313,862, filed January 15, 1940.

Other objects and features of the invention, including the shape of the control piston and the arrangement of restriction valves will be brought out in the following description and claims.

In the drawing: v

Fig, l is a sectional view illustrating a variable displacement pump diagrammatically and showing In detail the stroke control device.

Figs. 2 and 3 illustrate a portion of Fig. 1 showing the stroke control valve in a different relative position.

Referring to the drawing, in Fig. In control rod I43 is connected to a lever I44 which in turn i fastened to a rod I45, the function of which will be later described. The pump to be controlled is shown at'IBIl and is driven by an electric motor I6I. This pump is a reversible variable delivery pump having a shiftable control memberl66 to control the direction of flow of liquid through the pump and the displacement of the pump.

This type of pump is well known and will not be explained in detail except to say that when the movable head I66 is on one side of the center line, the flow through the pump will be in one direction, and when it is on the other side of the center line the flow through the pump will be in the other direction. The volume flow is always proportional to the displacement of the member I66 from the center line, that is, the greater the angle of the member I66 with the center line, the greater the volume output of the pump. It will be seen from this that as the member I66 crosses the center line the direction of flow through the pump will change.

The direction of liquid flow through the pump and the volume or displacement is indirectly controlled by the group or elements which consist of a stroke control piston I61, a pilot pressure control valve I68 and a pilot pressure pump I69. A relief valve H0 is provided to limit the output pressure of pump I69. The valve I68 is connected by a rod I46 and a lever I41 to shaft I45 previously described. The valve I68 is shiftable in a bore in a housing I to perform certain functions hereinafter described in detail. Leading from pump I69 is a conduit I" which connects to an annular port I8I in the valve housing I8Il. This port surrounds the bore of valve I68. When valve I68 is in the position shown in Fig. 1, pilot pressure from the pump I 69 may pass the valve to a second annular port I82 which leads to a conduit I83. The corresponding conduit I84 lead from the P rt I85 which will be connected to port I8I if valve I68 is shifted to the left from the position shown in Fig. 1. When conduit' I83 is connected to pressure it will be seen that conduit I84 is connected to. the tank through a conduit I86 and similarly, if conduit I8! is connected to pressure, conduit I83 will be connected to the tank through the conduit I 86.

The top part of the housing I 89 is provided with a recess in which reciprocates the stroke control piston I61. Thi recess consists of two spaced chambers I88 and I89 connected by a slightly restricted passage I98. Adjacent each end of the restricted passage are annular ports I! and I92; The stroke control piston consists of a rod I93, one end of which is connected to themember I66, and two piston spools I94 and I95. Each of these spools is tapered from a center portion which has a diameter arranged to have a sliding lit with the restricted portion I98 of the housing. The central portions of the spools are wide enough to cover the annular ports I91 and I92 if positioned directly over them. Conduits I83 and I84 each split three ways. The ports I9I and I92 are connected, respectively, to conduits I83 and. I84 through restrictions I96 and check valves I91 which permit flow from the ports to the conduit. The.outer ends of the two chambers I88 and I89 are connected to conduits I83 and I84, respectively, by conduits I98 in which are check valves I99 which permit flow from the conduits to the chambers. A third branch from conduits I83 and I84 consists of a restricted opening 200 which opens to the chambers I88 and I89 atabout the central portion.

' The restrictions I96 and 268 in housing I80 consist of small discs spaced in a cylindrical recess and provided with a small central aperture.

The operation of the control lever I43 may be either manual orit may be connected up to some operating element of a mechanism so thatv r versal is efiected automatically.

The stroke control piston I61 is particularly adapted for high speed operation. As the parts are viewed in Fig. 1, it will be seen that pilot pressure has just completed the movement of piston I61 to the left. As a result of this movement the volume control member I66 of the pump I60 has been shifted to its extreme left position as shown. When the lever I43 isv a ain shifted to effect a leftward movement of valve Hi8, pilot pressure may then be admitted from conduit I11 to conduit I84 while conduit 183 will be connected to the tank. In the movement of piston I61 to the right, pressure will pass to the left end of the piston through the restriction 200 and the check valve 199. The liquid on the right hand side of the piston I61 has, at the start of the movement, two outlets, one through check valve I91 and restriction M9 6 and the other through restriction 200. As the piston I61 reaches the mid-point of its movement so that part I66 is just passing dead-center, the port I 9| will be closed by the spool I95. At this time, it will be seen that the only outlet of liquid irom the right hand side of the piston I61 is the restriction 200. Consequently, there will be a gradual reduction in speed of the piston I61 as the tapered portion on spool I95 gradually closes oil port ISL Piston I61 is illustrated in its mid-position in Fig. 3. A piston I61 continues to the right, port l9! will again be gradually opened, and there will again be two outlets for the liquid to the right of the piston, namely, check valve I91 andthe restric-' tion 200. Piston I61 is shown in a second position in Fig. 2. The design of the stroke control piston liland the various outlets for the cylinder in which it is located, thus achieves a movement in which there is a gradual reduction of speed just prior to the mid-point of the movement and a gradual increase in speed beyond this point.

- The slow movement of the piston takes place at 1. In a hydraulic circuit, of .the type having a variable displacement pump, Qand a vshliftable member on said pump arranged to control direction of flow through said pump, a control system for said member comprising asource ofpilot pressure, means for directing said pilot-pressure, a control cylinder {or receiving said pilot pressure,

I a piston in said'control. cylinder adapted to be operatively connected to said shittable member,- and means for controlling the volume of liquid delivered to said last named piston whereby the movement of said piston insaid control cylinder is gradually decreased and then increased during the central portion of a stroke of said piston in &

changing the direction of the flow through said 7 pump.

2. In a hydraulic circuit, of the type having a variable displacement pump; and a shittable mem- I her on said pump arranged to control direction of flow through said pump, a control system for said member comprising a source of pilot pressure, means for directing said pilot pressure, a

control cylinder for receiving said pilot pressure, a. piston in said control cylinder adapted to be operatively connected to said shiftable member, said control cylinder having a plurality of restricted openings at each end adapted to serve as control outlets for liquid confined within said cylinder and a port formed in said cylinder connected to one of said outlets and adapted to be. temporarily closed during an intermediate portion of a stroke of the piston in said cylinder to effect gradual deceleration and acceleration at a predetermined intermediate point in the piston stroke during the change of direction of fluid flow in the variable displacement pump.

3. In a hydraulic circuit, of the type having a variable displacement pump, and a shiitable member on said pump arranged to control direction of flow through said pump, a control system for said member comprising a source of pilot pressure, means for directing said pilot pressure, a control cylinder for receiving said pilot pressure, a piston in said control cylinder adapted to be operatively connected to said shiitable member, said control cylinder having a plurality or restricted'openings at each end adapted to serve as control outlets for liquid confined within said cylinder and a port formed in said cylinder connected to one of said outlets and adapted .to be temporarily closed during portions oi a stroke of the piston in said cylinder to efiect gradual deceleration and acceleration at an intermediate point in the piston stroke and gradual deceleration at the end of a stroke.

4. In a hydraulic system, of the type having a reversible variable displacement pump, and movable means on said pump to control the direction and displacement thereof, a control means {or said movable means comprising a cylinder and a piston reciprocal therein, a rod on said piston adapted to be connected to said movable means, said cylinder comprising a housing having two spaced end chambers connected by a. passage slidably receiving said piston, unrestricted inlets to each of said chambers, restricted outlets from ports spaced in said passage, said pistoncomprlsing spaced portions to be slidably received by said passage and portions to each side of said spaced portions tapered to said spaced portions, said spaced portions being adapted to close said ports in passing them and being 56 arranged that one of said ports leading to an outlet will beclosed during intermediate and final stages of movement oi the piston to cause, during each closing, a gradual deceleration of the movement of the piston.

Y 5. In a hydraulic system, of the type having a reversible variable displacement 'pump, and movable means on said pump to control the direction and displacement thereof, a control meansfor said movable means comprising-a cylinder and a piston reciprocal therein, a rod on said piston adapted to be connected to said movable means, said control cylinder having a plurality of restricted openings at each end adapted to serve as'control outlets for liquid confined within said cylinder and a port formed in said cylinder connectcd to one of said outlets and adapted to be a connecting passage, conduits leading to each end of said cylinder, each conduit branching to the cylinder in a unidirectional unrestricted inlet, a restricted outlet leading to a port in said passage and a two-way restricted inlet-outlet, a piston in said cylinder adapted to slide in the passage therein and arranged at either end of its stroke and at an intermediate point to close one or more of said restricted outlets, said Piston comprising spaced portions to be slidably received by said passage, said spaced portions being adapted to close said ports in passing them and being so arranged that one of said-ports, leading to an outlet, will be closed during intermediate and final stages of movement of said piston to cause, during each closing, a gradual deceleration of the movement of the piston.

7. In a hydraulic system, a source of pressure, a means to be operated by pressure from said source including a cylinder comprising a housing having two spaced end chambers enlarged from a connecting passage, conduits leading to each end ot said cylinder, each conduit branching to the cylinder in a unidirectional unrestrictedinlet,

a restricted outlet leading to a-port in said passage and a two-way restricted inlet-outlet, a piston in said cylinder adapted to slide in the D 8- sage therein and arranged at either end of its stroke and at an intermediate point to close one or more of said restricted outlets, said piston comprising spaced portions to be slidably received by said passage, and portions to each side of said spaced portions tapered to said spaced portions. said spaced portions being adapted to close said ports in passing them and being so arranged that one of said ports, leading to an outlet, will be 6 closed during intermediate and final stages of movement or said piston to cause, during each closing, a gradual deceleration of the movement of the piston.

8. In a hydraulic system, a source of pressure, a means to be operated by pressure from said source including a cylinder comprising a housing having two spaced end chambers connected by a passage, conduits leading to each end of said cylinder, each conduit branching to the cylinder in a unidirectional unrestricted inlet, a restricted outlet leading to a,port in said passage and a two-way restricted inlet-outlet, a piston in said cylinder adapted to slide in the passage therein and arranged at either end of its stroke and at an intermediate point to close one or more of said restricted outlets, said piston comprising spaced portions to be slidably received by said passage, said spaced portions being. adapted to close said ports in passing them and being so arranged that one of said ports, leading to an outlet, will be closed during intermediate and final stages of movement of said piston to cause, during each closing, a gradual deceleration of the movement of the piston, valve means to alternately connect.

one of said conduit means to pressure and the other to tank, and valve means in said restricted outlets subject to pressure in said conduit means whereby when one of said conduit means is connected to pressure its respective restricted outlet will be closed and the other two branches thereof will serve as inlets to said cylinder.

HARRY IF. VICKERS. KENNETH R. HERMAN. JESSE MOSER. 

